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Electromagnet question

  1. Aug 4, 2008 #1
    1. does the length of an electromagnet effect how strong it is or where the magnetism is located?

    2. I am making an electromagnet and i am done with one layer how do i add one more do i start from where i started and go down or do i trail the wire to where i started.
  2. jcsd
  3. Aug 4, 2008 #2
    Google "making an electromagnet" without the quotes.

    You will see some great links. Happy experimenting!
  4. Aug 4, 2008 #3
    1. Yes, F = (u^2 N^2 I^2 A)/(2 u L^2)

    2. Your going to have to give us more detail for #2. Why would you add a second layer? Are you trying to make a transformer?
    Last edited: Aug 4, 2008
  5. Aug 10, 2008 #4
    I am adding the second layer to add more power. Right now i have i have a coil going all the way to the bottom now i want to add one more layer for more power which direction do i coil it.
  6. Aug 11, 2008 #5
    You wind it top to bottom, bottom to top, etc, and continue winding the wire in the same direction.
  7. Aug 11, 2008 #6
    i am confused, what do you mean same direction? If you look from the top down, you see the wire coiled in a clockwise rotation. I am trying to coil down do i do it in a clock wise rotation or a counter clockwise rotation
  8. Aug 11, 2008 #7
    As if you were winding a kite string around a stick, just keep on winding in the same direction. Any loops made in the opposite direction will merely negate the effect of a loop already made.

    Also, visualize a cable-winch spool on the front of a jeep. The cable is wound in one direction only. When the bottom layer is full (next to the spool) the second layer is subsequently wrapped on top of the first layer, and so on until the spool is full...all layers being wrapped in the same direction.
  9. Aug 11, 2008 #8
    so i would go down in a clock wise rotation
  10. Aug 17, 2008 #9
    a winch line is layered back and forth with a level wind mechanism, it would seem as if an electrical coil would benefit from the windings all going from the same side/direction ie; l to r then jumpiing back to l and starting over again.
  11. Aug 18, 2008 #10
    Not so. The effect of each loop in the winding is independent of its distance from either end of the spool. Any wire that is not forming part of a loop that is basically in a plane at right angles to the centerline of the spool is not contributing as much to the flux produced as it does when so formed. So, when you run the wire parallel to the centerline to get quickly from one end to the other, you are simply wasting wire and gaining nothing in magnetic flux.
  12. Aug 18, 2008 #11
    then what should i do
  13. Aug 18, 2008 #12


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    Wrap every turn clockwise, or wrap every turn counterclockwise. As long as it's the same for every turn.
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